The overarching goal of this research proposal is to develop and validate Natural Language Processing (NLP) algorithms for ascertainment of use, results, and techniques employed for EGFR and ALK testing, respectively, from SEER electronic pathology reports of stage IV non-squamous NSCLC cases. Successful achievement of this goal will occur through the accomplishment of the study objectives outlined below. Objectives: 1) Develop Natural Language Processing (NLP) algorithms to ascertain use, results, and techniques employed for EGFR and ALK testing, respectively, from SEER electronic pathology reports of stage IV non-squamous NSCLC registry cases diagnosed between 09/01/2011 and 12/31/2013. 2) Conduct a multiphase validation study of NLP algorithms for ascertainment of EGFR and ALK testing initially involving cases included in the Seattle Puget-Sound SEER registry, and posteriorly validating the NLP algorithms in the Kentucky SEER registry.